The present invention relates generally to flat bed type imaging devices and, more particularly, to flatbed imaging devices having a media clamp assembly.
Optical scanners create electronic data representative of a scanned object. Flatbed optical scanners are usually stationary devices which have a transparent, horizontally disposed, flat plate or platen upon which an object to be scanned, such as a document or photograph, may be placed. The document may be scanned by sequentially imaging narrow strips or scan line portions of the document on a linear optical sensor array such as a charged coupled device (CCD). In one type of flatbed scanner the current scan line portion of the document which is imaged on the sensor array is changed or xe2x80x9csweptxe2x80x9d by moving the platen supporting the document relative to the scanner imaging assembly.
In another, more popular, type of flatbed scanner the platen and document remain stationary and at least a portion of an imaging assembly is moved to change the scan line portion that is currently imaged. A flatbed optical scanner of the fixed platen type has a housing enclosing and shielding various optical and mechanical assemblies of the scanner. The scanner platen is mounted in an opening in a top portion of the housing. A carriage assembly, typically mounted on horizontal rails, is displaced below and parallel to the scanner platen. Fixed platen, flatbed scanners are disclosed in the following patents, each of which is hereby incorporated by reference for all that is disclosed therein: Boyd, U.S. Pat. No. 4,926,041; Henry et al., U.S. Pat. No. 5,339,107, Steinle et al., U.S. Pat. No. 5,410,347; and Steinle et al., U.S. Pat. No. 5,646,394.
In the absence of a mechanical feed device (automatic document feeder), most flatbed scanners are equipped with a cover or lid that is pivotally attached to the scanner housing so that it may be opened and closed like the cover of a book to expose or cover the platen. The lid is designed to cover the platen and any document placed on the platen during a scanning operation. Scanner lids are disclosed in U.S. patent application Ser. No. 09/016,562 of Batten et al., filed Jan. 30, 1998 for REFLECTOR FOR DOCUMENT SCANNER OR COPIER which is hereby incorporated by reference for all that it discloses.
A problem encountered in using flatbed scanners equipped with lids is that air movement is created by closing the lid on a document. The document, which has typically been placed at a desired location and orientation on the platen, is displaced as a result of the air movement. Often the displacement takes place during the very last stage of lid closing and thus goes unnoticed until after a scan has been made. Another related problem with document placement occurs because of static electricity which sometimes builds up on sheet media as a result of sliding against other sheets, etc. This static buildup can create a nearly friction-free interface between a sheet to be scanned and the scanner platen. As a result the sheet xe2x80x9cslides aroundxe2x80x9d on the platen in response to any bumps or jolts to furniture that supports the scanner or as a result of any deviation from a horizontal orientation of the platen, as well as xe2x80x9cwindxe2x80x9d caused by closing the lid.
A flatbed optical scanner is one type of imaging device that encounters the above-described problems. Similar problems exist for other flatbed-type imaging devices such as digital imaging devices that use two dimensional photodetector arrays (rather than the one dimensional arrays used by conventional scanners), photocopy machines (conventional and digital), etc. As used herein, the term xe2x80x9cimaging devicexe2x80x9d includes optical scanners, digital imagers with two-dimensional sensors, photocopiers, and other similar devices.
The applicants perceive that a need exists for a method and apparatus to maintain a document at a fixed orientation on a scanner platen to prevent the displacements without interfering with the scanner lid or with the scanning operation.
The present invention is directed towards a scanner. The scanner may have a transparent, media support platen provided with a first surface portion and a second surface portion. The scanner may also have a media clamp mounted in displaceable, overlying relationship with the first surface portion of the platen. Additionally, the scanner may have a lid mounted in displaceable overlying relationship with the second surface portion of the platen.
The present invention is also a scanner provided with a transparent means for supporting an object to be imaged. The scanner may also have a means for clamping the object to the transparent means and for partially light blockingly covering the transparent means. Additionally, the scanner may have a means for light blockingly covering all portions of the transparent means not covered by the means for clamping.
The present invention is also a method of imaging at least one object by holding a first object against a platen with a clamp, and then covering a portion of the platen not covered by the clamp with a lid.
The present invention is also a method of imaging an object by biasingly urging a portion of the object against a first side of a platen and then illuminating the object from a second side of the platen opposite the first side.